You do realize virtual interfaces don't exist in linux anymore? they are only used to display it easy to the user.
One of the things about ipv6 was to do away with the whole one ip per interface thing. You can define as many as you want, and no alias needed.
Just use, ifconfig eth0 add xxxx, for as many ip's as you need.
Or since ifconfig is technically been removed, but kept around for compatability, use the ip command directly, ip addr add ....